Spring Manufacturing Machine

ABSTRACT

A spring manufacturing machine comprises a coiling mandrel fixed to a wall and protruding from the wall, and a cutting device that has a slider movable in a direction inclined with respect to the axis of the coiling mandrel and a blade attached to the slider, and cuts a bent wire in cooperation with the coiling mandrel. Preferably, the coiling mandrel protrudes orthogonally to the wall, and the cutting device is attached to the wall in a posture inclined with respect to the wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2019-000635 filed in Japan on Jan. 7,2019, the entire contents of which are hereby incorporated by reference.

FIELD

The present technology relates to a spring manufacturing machine thatmanufactures a spring by bending a wire.

BACKGROUND AND SUMMARY

A spring manufacturing machine comprises, rollers attached to the frontsurface of a wall, a bending die, and a cutting device. The wire sentout by the rollers is bent by the bending die and is cut by the cuttingdevice, whereby a spring is manufactured. The wall of the springmanufacturing machine may have a cutting tool support wall inclined soas to descend toward the rear, and the cutting tool support wallsupports a pair of opposing cutting tools.

The pair of cutting tools come into contact with each other and go awayfrom each other in the opposing direction. One cutting tool is insertedinto the inside of a wound wire (coil) from the rear end portion of thecoil, the other cutting tool approaches the wound wire from the outside,and the wire is sandwiched between the two cutting tools to be cut.

When the inside diameter of the spring to be manufactured is small, thegap for inserting the cutting tool is also small, so that it isimpossible to insert the one cutting tool into the inside of the woundwire. As a consequence, when the wire is cut, there is a possibilitythat the one cutting tool interferes with a part of the wire other thanthe part to be cut and this makes it impossible to precisely manufacturethe spring.

The present disclosure is made in view of such circumstances, and anobject thereof is to provide a spring manufacturing machine with whicheven when a spring with a small inside diameter is manufactured, theinterference with a part of the wire other than the part to be cut isprevented to make it possible to precisely manufacture the spring.

A spring manufacturing machine according to the present disclosurecomprises: a coiling mandrel fixed to a wall and protruding from thewall; and a cutting device that has a slider movable in a directioninclined with respect to an axis of the coiling mandrel and a bladeattached to the slider, and cuts a bent wire in cooperation with thecoiling mandrel.

In the present disclosure, the wire is cut by the coiling mandrel fixedto the wall and the cutting device. When a spring with a small insidediameter is manufactured, a coiling mandrel with dimensionscorresponding to the inside diameter is used. For this reason, even whena spring with a small inside diameter is manufactured, the blade doesnot interfere with a part of the wire other than the part to be cut.

When the dimensions of the coiling mandrel correspond to a spring with asmall inside diameter, for example, a spring where a so-called springindex is not more than 4, a cross-sectional area of the end portion ofthe coiling mandrel taken along a surface orthogonal to the axis issmall, so that if the load acting on the coiling mandrel at the time ofcutting concentrates in a radial direction, the coiling mandrel readilybreaks. In the present disclosure, since the slider and the blade movein a direction inclined with respect to the axis of the coiling mandrel,the load acting on the coiling mandrel at the time of cutting of thewire acts not only in the radial direction of the coiling mandrel butalso in an axial direction thereof. That is, the load acting on thecoiling mandrel is dispersed in the radial direction and in the axialdirection.

In the spring manufacturing machine according to the present disclosure,the coiling mandrel protrudes orthogonally to the wall, the cuttingdevice is attached to the wall in a posture inclined with respect to thewall, and an angle of inclination of the cutting device with respect tothe wall is not more than 30 degrees.

In the present disclosure, by making not more than 30 degrees the angleof inclination of the cutting device with respect to the wall, it ismade easy to cut the wire in a desired position. Moreover, the distancebetween the end portion of the cutting device and the wall is preventedfrom becoming excessive, and the overall rigidness of the springmanufacturing machine is prevented from decreasing.

The spring manufacturing machine according to the present disclosure isprovided with an adjustment mechanism that adjusts the posture of thecutting device.

In the present disclosure, the wire is cut at an appropriate anglecorresponding to the kind of the wire and the spring index by adjustingthe posture of the cutting device.

In the spring manufacturing machine according to the present disclosure,the blade has a parallel portion parallel to the axis of the coilingmandrel, and the wire is sandwiched between the parallel portion and thecoiling mandrel to be cut.

In the present disclosure, by forming the parallel portion on the bladeof the cutting device, when the cutting device is moved along a circularlocus to cut the wire, the cutting device is prevented from interferingwith the coiling mandrel.

With the spring manufacturing machine according to the presentdisclosure, the wire is cut by the coiling mandrel fixed to the wall andthe cutting device. When a spring with a small inside diameter ismanufactured, a coiling mandrel with dimensions corresponding to theinside diameter is used. For this reason, even when a spring with asmall inside diameter is manufactured, the blade does not interfere witha part of the wire other than the part to be cut, so that the spring canbe precisely manufactured. When the dimensions of the coiling mandrelcorrespond to a spring with a small inside diameter, for example, aspring where a so-called spring index is not more than 4, thecross-sectional area of the end portion of the coiling mandrel takenalong the surface orthogonal to the axis is small, so that if the loadacting on the coiling mandrel at the time of cutting concentrates in theradial direction, the coiling mandrel readily breaks. In the presentdisclosure, since the slider and the blade move in a direction inclinedwith respect to the axis of the coiling mandrel, the load acting on thecoiling mandrel at the time of cutting of the wire acts not only in theradial direction of the coiling mandrel but also in the axial directionthereof. That is, the load acting on the coiling mandrel is dispersed inthe radial direction and in the axial direction. Compared with when thecutting device moves in a direction orthogonal to the axis of thecoiling mandrel, the load acting in the radial direction of the coilingmandrel is low, so that the coiling mandrel is difficult to break.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a spring manufacturing machineaccording to a first embodiment.

FIG. 2 is a schematic front view of the spring manufacturing machine.

FIG. 3 is an enlarged right side view schematically showing a cuttingdevice support wall and a cutting device.

FIG. 4 is an enlarged front view schematically showing wire sendingrollers, a blade, a coiling mandrel and the like.

FIG. 5 is an enlarged right side cross-sectional view schematicallyshowing the cutting device and the coiling mandrel.

FIG. 6 is a schematic front view of a spring manufacturing machineaccording to a second embodiment.

FIG. 7 is a vertical cross section taken along the line VII-VII shown inFIG. 6.

FIG. 8 is a perspective view schematically showing a springmanufacturing machine according to a modification.

FIG. 9 is an enlarged right side view schematically showing a cuttingdevice support wall and a cutting device of a spring manufacturingmachine according to a third embodiment.

FIG. 10 is an enlarged front view schematically showing wire sendingrollers, a blade, a coiling mandrel and the like.

FIG. 11 is an enlarged right side cross-sectional view schematicallyshowing the cutting device and the coiling mandrel.

FIG. 12 is an enlarged front explanatory view explaining a movementlocus of the blade.

FIG. 13 is an enlarged right side explanatory view explaining a movementlocus of a blade of a spring manufacturing machine according to a fourthembodiment.

DETAILED DESCRIPTION OF NON-LIMITING EXAMPLE EMBODIMENTS FirstEmbodiment

Hereinafter, the present invention will be described based on thedrawings showing a spring manufacturing machine according to a firstembodiment. In the following description, the top, the bottom, thefront, the rear, the right and the left shown in the figures are used.FIG. 1 is a schematic perspective view of the spring manufacturingmachine, and FIG. 2 is a schematic front view of the springmanufacturing machine.

The spring manufacturing machine is provided with a first supportportion 1. The first support portion 1 is provided with: a bottomportion 1 a that is rectangular in top view; a front wall 1 b extendingupward from the front edge of the bottom portion 1 a; a left portion 1 cextending upward from the left edge of the bottom portion 1 a; and anupper portion 1 d continuous with the upper ends of the left portion 1 cand the front wall 1 b and opposed to the bottom portion 1 a.

On the front surface of the front wall 1 b, a plurality of wire sendingrollers 3 are supported so as to be rotatable around an axis extendingin the front-rear direction. The wire sending rollers 3 are arranged intwo rows one above the other, and the rollers in the upper row and therollers in the lower row are opposed to each other. Between the wiresending rollers 3 and next to the wire sending rollers 3, wire guides 4are provided. The wire guides 4 are block-shaped, and a groove where awire 20 passes is formed.

On the left side of the first support portion 1, a wire supply device(not shown) that supplies the wire 20 to the wire sending rollers 3 isprovided, and on the rear side of the first support portion 1, a motor(not shown) that drives the wire sending rollers 3 is provided. The wire20 is supplied from the wire supply device to the wire sending rollers3, the wire 20 is sandwiched between the upper and lower wire sendingrollers 3, the upper wire sending rollers 3 rotate counterclockwise infront view, and the lower wire sending rollers 3 rotate clockwise infront view. The wire 20 is guided by the wire guides 4 to be sent fromthe left to the right.

The spring manufacturing machine is provided with a second supportportion 2. The second support portion 2 is disposed next to the firstsupport portion 1 on the right, and the first support portion 1 and thesecond support portion 2 are separated from each other in the right-leftdirection. The second support portion 2 is provided with: a bottomportion 2 a that is rectangular in top view; a front wall 2 b extendingupward from the front edge of the bottom portion 2 a; a right portion 2c extending upward from the right edge of the bottom portion 2 a; and anupper portion 2 d continuous with the upper ends of the right portion 2c and the front wall 2 b and opposed to the bottom portion 2 a.

On the front wall 2 b of the second support portion 2, a first toolattachment 5 and a second tool attachment 6 are supported. The firsttool attachment 5 is provided with a slider 5 a extending in theright-left direction and an attachment portion 5 b attached to the leftend portion of the slider 5 a. The slider 5 a is movable in theright-left direction. To the attachment portion 5 b, a tool, in thepresent embodiment, a bending die 5 c is attached. The bending die 5 cis provided with a groove that guides the wire 20 in order to ensure thebending of the wire 20. The attachment portion 5 b of the first toolattachment 5 is opposed to the wire guide 4 disposed on the rightmostside.

The second tool attachment 6 is disposed above the first tool attachment5. The second tool attachment 6 is provided with a slider 6 a inclinedso as to descend toward the left and an attachment portion 6 b attachedto the lower end portion of the slider 6 a. The slider 6 a is movable inthe inclination direction. To the attachment portion 6 b, a tool, in thepresent embodiment, a bending die 6 c is attached. The attachmentportion 6 b of the second tool attachment 6 is disposed obliquely rightabove the wire guide 4 disposed on the rightmost side. Tools other thanthe bending dies 5 c and 6 c may be attached to the attachment portions5 b and 6 b.

FIG. 3 is an enlarged right side view schematically showing a cuttingdevice support wall 7 and a cutting device 8. The alternate long andshort dash line of FIG. 3 represents an extension line from the frontsurface of the cutting device support wall 7. The cutting device supportwall 7 is provided between the first support portion 1 and the secondsupport portion 2. The cutting device support wall 7 extends in thetop-bottom direction. The cutting device 8 is supported on the upperpart of the front surface of the cutting device support wall 7. Thecutting device 8 is provided with a rail mount 9, a crank mechanism 10,a slider 11 and a blade 13. The rail mount 9 extends in the top-bottomdirection. As shown in FIG. 1 and FIG. 3, the rail mount 9 is inclinedso as to protrude forwardly as a position of the rail mount 9 is locatedupwardly with respect to the front surface of the cutting device supportwall 7. In other words, the posture of the rail mount 9 is a forwardleaning posture. The angle θ formed between the rear surface of the railmount 9 and the front surface of the cutting device support wall 7 isset to not more than 30 degrees, for example, 20 degrees.

On a lower part of the front surface of the rail mount 9, a rail 9 a isprovided that extends in the top-bottom direction in the inclinationdirection of the rail mount 9. On the rail 9 a, the slider 11 isslidably provided through sliding elements 12. On the upper end portionof the rail mount 9, the crank mechanism 10 is provided. The crankmechanism 10 is provided with: a motor 10 d attached to the upper endportion of the rail mount 9; a rotating disk 10 a with a rotation axisextending in the front-rear direction; and a coupling plate 10 c. To thecenter of the rotating disk 10 a, a rotation shaft of the motor 10 d iscoaxially coupled. The coupling plate 10 c extends in the top-bottomdirection, and the upper end portion of the coupling plate 10 c and therotating disk 10 a are coupled together through a pivot 10 b. The pivot10 b is disposed in a position away from the rotation center of therotating disk 10 a. The lower end portion of the coupling plate 10 c andthe slider 11 are coupled together through a pivot (not shown). To thelower end portion of the slider 11, the blade 13 that cuts the wire 20is attached. The rotation of the motor 10 d is converted to a movementin the top-bottom direction by the crank mechanism 10, and the slider 11and the blade 13 make a linear movement in the top-bottom direction inthe inclination direction of the rail mount 9.

FIG. 4 is an enlarged front view schematically showing the wire sendingrollers 3, the blade 13, a coiling mandrel 15 and the like, and FIG. 5is an enlarged right side cross-sectional view schematically showing thecutting device 8 and the coiling mandrel 15. In FIG. 5, the alternatelong and short dash line represents an axial center 15 d of asemicircular column portion 15 a, and the alternate long and two shortdashes line represents a vertical line N orthogonal to the axial center15 d. On the lower side of the cutting device 8, the coiling mandrel 15is provided. The coiling mandrel 15 is columnar, and protrudes forwardfrom the front surface of the cutting device support wall 7. On thefront end portion of the coiling mandrel 15, the semicircular columnportion 15 a is formed. The front shape of the semicircular columnportion 15 a is a semicircular shape having an arc swelling so as toprotrude rightward and a chord coupling the upper end and the lower endof the arc. The semicircular shape is not limited to a shape where theratio between the length of the chord (longitudinal length) and thelength in the direction orthogonal to the chord (lateral length) is 2:1but includes a shape where the ratio is 2:1.3 or the like. The left sidesurface (surface corresponding to the chord) of the semicircular columnportion 15 a forms a sliding surface 15 b where the blade 13 slides. Thepart of the coiling mandrel 15 behind the semicircular column portion 15a (hereinafter, referred to as the rear part of the coiling mandrel 15)has a rectangular parallelepiped shape. The left side surface of thesemicircular column portion 15 a and the left side surface of the rearpart of the coiling mandrel 15 are substantially flush with each other.The cross-sectional area of the rear part of the coiling mandrel 15 onthe cross section orthogonal to the axis is larger than thecross-sectional area of the semicircular column portion 15 a.

The blade 13 has a rectangular parallelepiped shape, and extends in thetop-bottom direction in the inclination direction of the rail mount 9.That is, like the posture of the rail mount 9, the posture of the blade13 is a forward leaning posture. As shown in FIG. 4, on the bottomsurface of the blade 13, an inclined surface 13 a is formed that isinclined so as to descend toward the right. As shown by the arrow ofFIG. 5, the blade 13 moves up obliquely forward and moves down obliquelyrearward. In other words, in side view, the blade 13 of the cuttingdevice 8 is movable in a direction inclined with respect to the axialcenter 15 d. The angle of inclination of the blade 13 with respect tothe vertical line N orthogonal to the axial center 15 d is substantiallythe same as the above-mentioned angle θ. The cutting device 8 ispositioned so that the right side surface of the blade 13 and thesliding surface 15 b of the semicircular column portion 15 a aresubstantially flush with each other.

The wire 20 sent out rightward by the wire sending rollers 3 abuts onthe grooves of the bending dies 5 c and 6 c, and is bent so as tosurround the peripheral surface of the semicircular column portion 15 a.The wire 20 having been bent is in coil form, and is grown toward thefront. The slider 11 moves down, and the upper side of the rear endportion of the wire 20 formed in coil form is sandwiched between the endof the inclined surface 13 a of the blade 13 and an upper edge 15 c ofthe sliding surface 15 b (hereinafter, the wire 20 formed in coil formwill be referred to also as coil or coil spring). The slider 11 furthermoves down and cuts the wire 20. Thereafter, the slider 11 moves up. Theblade 13 cuts only the rear end portion of the coil. The axial center 15d is substantially parallel to the axial center of the coil and theaxial center of the entire coiling mandrel 15.

The cutting device support wall 7 may be formed of one member or may beformed of a plurality of members. For example, the cutting devicesupport wall 7 may be provided with a member supporting the coilingmandrel 15 and a member supporting the cutting device 8. Moreover, thecutting device 8 and the coiling mandrel 15 are formed so as to bemovable in the top-bottom direction. The manufacturer changes thepositions, in the top-bottom direction, of the cutting device 8 and thecoiling mandrel 15 according to the diameter of the spring to bemanufactured.

With the spring manufacturing machine according to the first embodiment,the wire 20 is cut by the coiling mandrel 15 fixed to the cutting devicesupport wall 7 and the blade 13 attached to the slider 11. When a springwith a small inside diameter is manufactured, the coiling mandrel 15with dimensions corresponding to the inside diameter is used. For thisreason, even when a spring with a small inside diameter is manufactured,the part to be cut of the wire 20, for example, the upper end portion ofthe wound wire 20 can be cut.

When the dimensions of the coiling mandrel 15 correspond to a springwith a small inside diameter, for example, a spring where a so-calledspring index is not more than 4, the cross-sectional area of the endportion (the semicircular column portion 15 a) of the coiling mandrel 15taken along a surface orthogonal to the axial center 15 d is small, sothat if the load acting on the coiling mandrel 15 at the time of cuttingconcentrates in the radial direction, the coiling mandrel 15 readilybreaks. For this reason, conventionally, it is necessary to design thecoiling mandrel 15 so that the cross-sectional area of the semicircularcolumn portion 15 a is small while the strength is maintained. In theabove-described spring manufacturing machine, since the slider 11 andthe blade 13 move in a direction inclined with respect to the axis ofthe coiling mandrel 15, the load acting on the coiling mandrel 15 fromthe cutting device 8 at the time of cutting of the wire 20 acts not onlyin the radial direction of the coiling mandrel 15 but also in the axialdirection thereof. That is, the load acting on the coiling mandrel 15 isdispersed in the radial direction and in the axial direction. Comparedwith when the slider 11 and the blade 13 move in a direction orthogonalto the axial center 15 d of the coiling mandrel 15, the load acting inthe radial direction of the coiling mandrel 15 is low, so that thecoiling mandrel 15 is difficult to break. As a result, the burden on thedesigner is reduced in designing the coiling mandrel 15.

When the angle θ exceeds 30 degrees, there is a possibility that notonly the rear end portion of the coil but also the center side portionof the coil is cut. By making not more than 30 degrees the angle θ ofinclination of the cutting device 8 with respect to the cutting devicesupport wall 7, it is made easy to cut only the rear end portion of thecoil. Moreover, the distance between the upper end portion of thecutting device 8 and the cutting device support wall 7 is prevented frombecoming excessive, and the overall rigidness of the springmanufacturing machine is prevented from decreasing.

Here, the median diameter (the median value between the inside diameterand the outside diameter) of the coil spring is D and the diameter ofthe wire 20 is d. D/d is a spring index. It is typical to select thewire 20 so that the spring index D/d>4 when the slider 11 is moved inthe vertical direction. This is because when D/d≤4, the shearing forceacting on the coiling mandrel 15 from the cutting device 8 (a forceacting in the radial direction of the coiling mandrel 15 or a forceacting in a direction orthogonal to the axial center 15 d) is excessiveand this increases the possibility that the coiling mandrel 15 breaks.By making the posture of the cutting device 8 oblique, the load actingon the coiling mandrel 15 is dispersed in the radial direction and inthe axial direction, so that even when the spring index D/d≤4, theshearing force acting on the coiling mandrel 15 from the cutting device8 does not readily become excessive.

As the material of the coiling mandrel 15, for example, a super hardalloy or a high-speed steel is used. When the super hard alloy is used,since the hardness of the coiling mandrel 15 is very high, for example,even if an oil-tempered wire which is a heat-treated materialcomparatively high in hardness is used for the wire 20, the wire 20 canbe cut with burr generation being suppressed. However, the super hardalloy has a characteristic of being fragile, and when the slider 11 ismoved in the vertical direction, the shearing force acting on thecoiling mandrel 15 from the blade 13 is excessive, so that there is apossibility that the coiling mandrel 15 breaks. For this reason,conventionally, when D/d≤4, that is, when the median diameter D of thecoil spring decreases or the diameter d of the wire 20 increases todecrease the spring index, a high-speed steel is used as the material ofthe coiling mandrel 15. This is because the high-speed steel is higherin toughness than the super hard alloy and does not readily break.However, since the high-speed steel is prone to be plastically deformedcompared with the super hard alloy and has a characteristic of beingeasy to wear, when the high-speed steel is used for the coiling mandrel15 and the above-mentioned high hardness wire 20 is cut, burr generationreadily occurs on the wire 20 compared with when the super hard alloy isused for the coiling mandrel 15. The oil-tempered wire is high inhardness compared with the piano wire, the hard steel wire, thestainless steel wire or the like.

In the first embodiment, as described above, since the load acting onthe coiling mandrel 15 is dispersed in the radial direction and in theaxial direction by making the posture of the cutting device 8 oblique,even when the spring index is lower than a predetermined value,specifically, when D/d≤4, by selecting the super hard alloy as thematerial of the coiling mandrel 15, it is possible to cut the highhardness wire 20 with burr generation being suppressed and prevent thebreakage of the coiling mandrel 15. By suppressing burr generation,high-quality coil springs can be continuously manufactured.

As described above, the load acting on the coiling mandrel 15 isdispersed in the radial direction and in the axial direction. For thisreason, even if burrs are generated, the burrs are readily directed inthe axial direction, and the burrs are difficult to protrude inward inthe radial direction of the coil, so that the degradation in the qualityof the coil spring can be suppressed.

In the first embodiment, although the cutting device 8 moves downobliquely rearward, the cutting device 8 may move down obliquelyforward. When the cutting device 8 moves down obliquely rearward, arearward force in the axial direction acts on the coiling mandrel 15.When the cutting device 8 moves down obliquely forward, a forward forcein the axial direction acts on the coiling mandrel 15. As describedabove, the rear portion of the coiling mandrel 15 is larger incross-sectional area than the front portion (the semicircular columnportion 15 a) and is higher in rigidness than the front portion. Forthis reason, on the coiling mandrel 15, the action of the rearward forcein the axial direction is preferable in view of strength to the actionof the forward force in the axial direction, and it is preferablebecause the coiling mandrel 15 is difficult to move forward in the axialdirection. When the coiling mandrel 15 moves forward, there is apossibility that the cut spring is caught on the coiling mandrel 15 andremains on the coiling mandrel 15.

The conventional spring manufacturing machine described in JapanesePatent No. 6,403,224 is provided with an inclined cutting tool supportwall and two cutting tools supported by the cutting tool support wall.The two cutting tools are brought close to each other to cut the upperend portion of the wire. One cutting tool is inserted into the inside ofthe coil through a gap in the neighborhood of the rear end portion ofthe wound wire (coil), the other cutting tool approaches the coil fromthe outside, the wire is sandwiched between the two cutting tools, andthe upper end portion of the coil is cut. However, when the insidediameter of the coil is small, the gap is also small, the one cuttingtool cannot be inserted into the inside of the coil, and the one cuttingtool interferes with the lower part of the coil, so that there is apossibility that the spring cannot be precisely manufactured.

On the other hand, the spring manufacturing machine according to thefirst embodiment is capable of precisely manufacturing the springwithout the blade 13 interfering with a part of the coil other than thepart to be cut, for example, the lower end portion of the coil.

Second Embodiment

Hereinafter, the present invention will be described based on thedrawings showing a spring manufacturing machine according to a secondembodiment. Of the elements according to the second embodiment, elementssimilar to those of the first embodiment are denoted by the samereference numerals and detailed descriptions thereof are omitted. FIG. 6is a schematic front view of the spring manufacturing machine, and FIG.7 is a vertical cross section taken along the line VII-VII shown in FIG.6.

To the front surface of the cutting device support wall 7, a supportmount 14 is fixed. The support mount 14 and the lower end portion of therail mount 9 are coupled together through a pivot 7 a with theright-left direction as the axial direction. The rail mount 9 isrotatable around the pivot 7 a. That is, the cutting device 8 is capableof changing the angle of inclination with respect to the cutting devicesupport wall 7.

To the upper portion 2 d of the second support portion 2, a motor 16 isattached. The rotation shaft of the motor 16 and the rail mount 9 arecoupled together through a rotating plate 17. The rotating plate 17 isoval, and to one end portion thereof, the rotation shaft of the motor 16is orthogonally coupled. On the other end portion of the rotating plate17, a guide hole 17 a is formed. The guide hole 17 a passes through therotating plate 17 and is in the form of an oblong hole elongated in thelength direction of the rotating plate 17. The rail mount 9 is providedwith a protruding portion 9 b protruding rightward, and the protrudingportion 9 b is inserted into the guide hole 17 a.

The rotating plate 17 is rotated by the rotation of the motor 16. Theprotruding portion 9 b is guided by the guide hole 17 a, the position ofthe protruding portion 9 b is changed, and the angle of inclination ofthe cutting device 8 with respect to the cutting device support wall 7is changed. That is, the posture of the cutting device 8 is adjusted.The inclination angle of the cutting device 8 can be adjusted until theposture becomes a desired one.

With the spring manufacturing machine according to the secondembodiment, the wire 20 can be cut at an appropriate angle correspondingto the kind of the wire 20 and the spring index by adjusting the postureof the cutting device 8.

FIG. 8 is a perspective view schematically showing a springmanufacturing machine according to a modification. The springmanufacturing machine according to the modification uses an adjustmentplate 21 instead of the rotating plate 17. The upper portion 1 d of thefirst support portion 1 and the rail mount 9 are coupled togetherthrough the adjustment plate 21. The adjustment plate 21 is oval, and aguide hole 21 a is formed on one end portion thereof. The guide hole 21a passes through the adjustment plate 2 and is in the form of an oblonghole elongated in the length direction of the adjustment plate 21.

On the upper end portion of the cutting device support wall 7, aprotruding portion 7 b protruding rightward is formed. The protrudingportion 7 b is inserted in the guide hole 21 a of the adjustment plate21. The other end portion of the adjustment plate 21 is connected to therail mount 9 through a pivot 9 c with the right-left direction as theaxial direction. The user can position the cutting device 8 at anappropriate angle by rotating the rail mount 9 around the pivot 7 a (seeFIG. 7) to fix the protruding portion 7 b by the guide hole 21 a. Thepositioning of the cutting device 8 may be automatically performed byusing a motor or may be manually performed.

Third Embodiment

Hereinafter, the present invention will be described based on thedrawings showing a spring manufacturing machine according to a thirdembodiment. Of the elements according to the third embodiment, elementssimilar to those of the first or the second embodiment are denoted bythe same reference numerals and detailed descriptions thereof areomitted. FIG. 9 is an enlarged right side view schematically showing thecutting device support wall 7 and the cutting device 8.

The slider 11 is provided with a rear portion 11 a and a front portion11 b. The rear portion 11 a extends in the top-bottom direction alongthe rail mount 9. The upper end portion of the rear portion 11 a and therotating disk 10 a are coupled together through the coupling plate 10 c.The rear portion 11 a is slidably provided on the rail 9 a through thesliding elements 12. The front portion 11 b is provided on the frontside of the rear portion 11 a. The front portion 11 b and the rearportion 11 a are coupled together by a pivot 11 c. The axial directionof the pivot 11 c is a direction orthogonal to the inclination directionof the rail mount 9. To the lower end portion of the front portion lib,the blade 13 is attached.

FIG. 10 is an enlarged front view schematically showing the wire sendingrollers 3, the blade 13, the coiling mandrel 15 and the like, and FIG.11 is an enlarged right side cross-sectional view schematically showingthe cutting device 8 and the coiling mandrel 15. As shown in FIG. 10 andFIG. 11, on the left part of the bottom surface of the blade 13, theinclined surface 13 a inclined so as to descend toward the right and aparallel surface 13 b continuous with the right end of the inclinedsurface 13 a and parallel to the axial center 15 d of the semicircularcolumn portion 15 a are formed. The parallel surface 13 b is formed onlyon the right front end portion of the bottom surface of the blade 13.

FIG. 12 is an enlarged front explanatory view explaining a movementlocus of the blade 13. In FIG. 12, the solid arrow shows the movementlocus of the blade 13. The rear portion 11 a of the slider 11 linearlymoves in the top-bottom direction along the rail 9 a by the driving ofthe crank mechanism 10. Since the front portion 11 b of the slider 11 iscoupled to the rear portion 11 a through the pivot 11 c, it swings inthe right-left direction with respect to the rear portion 11 a. For thisreason, the blade 13 moves in the top-bottom direction and in theright-left direction, and as shown by the solid line of FIG. 12, themovement locus of the blade 13 (more specifically, the movement locus ofthe parallel surface 13 b) is an oval elongated in the top-bottomdirection. The position of the cutting device 8 is set so that the lowerend portion of this oval is situated at the upper end portion of thewire 20 formed in coil form.

The wire 20 sent out rightward by the wire sending rollers 3 abuts onthe grooves of the bending dies 5 c and 6 c, and is bent so as tosurround the peripheral surface of the semicircular column portion 15 a.The wire 20 having been bent is in coil form, and is grown toward thefront. The blade 13 moves down along the oval locus, and the upper sideof the rear end portion of the wire 20 formed in coil form is sandwichedbetween the parallel surface 13 b of the blade 13 and the upper edge 15c of the sliding surface 15 b. The blade 13 cuts the wire 20 and movesup. The parallel surface 13 b cuts only the rear end portion of thecoil.

The broken line arrow of FIG. 12 shows the movement locus of the blade13 when a blade 13 similar to the blade 13 of the first embodiment, thatis, a blade 13 where the parallel surface 13 b is not formed is used. Asshown by the broken line arrow, when the parallel surface 13 b is notformed, the movement locus is an oval elongated in the top-bottomdirection. The lower end portion of this oval is situated below theupper end of the coiling mandrel 15. That is, it interferes with thecoiling mandrel 15. When the position of the blade 13 is moved upward inorder to prevent the interference with the coiling mandrel 15, there isa possibility that cutting of the coil is insufficient and the coilcannot be cut.

With the spring manufacturing machine according to the third embodiment,by forming the parallel portion on the blade 13 of the slider 11, whenthe blade 13 is moved along a circular locus, for example, along an ovallocus to cut the wire 20, the blade 13 is prevented from interferingwith the coiling mandrel 15 and the wire 20 can be surely cut. Moreover,compared with when the blade 13 is linearly moved, burr generation isdifficult to occur on the coil, so that the degradation in the qualityof the coil spring can be suppressed.

Fourth Embodiment

Hereinafter, the present invention will be described based on thedrawings showing a spring manufacturing machine according to a fourthembodiment. Of the elements according to the fourth embodiment, elementssimilar to those of the first to third embodiments are denoted by thesame reference numerals and detailed descriptions thereof are omitted.FIG. 13 is an enlarged right side explanatory view explaining a movementlocus of the blade 13. The arrow of FIG. 13 shows the movement locus ofthe blade 13. By driving the motor 16 while moving the slider 11 in thetop-bottom direction, the rail mount 9 is swung around the pivot 7 a inthe front-rear direction. The blade 13 moves in the top-bottom directionand in the right-left direction, and as shown by the arrow of FIG. 13,the movement locus of the blade 13 is an oval elongated in thetop-bottom direction.

A structure may be adopted in which the slider 11 is formed of two partsof a right portion and a left portion, these are coupled together by apivot with the right-left direction as the axial direction, one isattached to the rail 9 a and the other is attached to the blade 13. Inthis case, the blade 13 can be swung in the front-rear direction withoutthe motor 16 being driven.

The above-described spring manufacturing machine in which the cuttingdevice 8 is disposed above the coiling mandrel 15 manufactures aright-hand coil. When a left-hand coil is manufactured, the cuttingdevice 8 is disposed below the coiling mandrel 15.

The spring manufacturing machine is capable of manufacturing not onlythe coil spring but also other kinds of springs. For example, a ringspring can be manufactured. When a ring spring is manufactured, theshape of the end portion of the coiling mandrel does not have to be asemicircle and may be, for example, a rectangular parallelepiped.Moreover, the angle of inclination of the cutting device 8 with respectto the cutting device support wall 7 does not have to be not more than30 degrees and may be, for example, an arbitrary angle in a range of 30degrees to 90 degrees. Moreover, the movement locus of the blade 13 doesnot have to be a circle or an oval and may be, for example, a line.

The embodiments disclosed herein should be considered as illustrative inall respects and not restrictive. The technical features described inthe embodiments may be combined together, and it is intended that allchanges within the scope of the claims and the scope equivalent to thescope of the claims are embraced by the scope of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

7 Cutting device support wall (wall)

8 Cutting device

9 Rail mount

9 b Protruding portion (adjustment mechanism)

13 Blade

13 b Parallel surface (parallel portion)

15 Coiling mandrel

15 a Semicircular column portion

15 d Axial center

16 Motor (adjustment mechanism)

17 Rotating plate (adjustment mechanism)

17 a Guide hole (adjustment mechanism)

20 Wire

What is claimed is:
 1. A spring manufacturing machine comprising: acoiling mandrel fixed to a wall and protruding from the wall; and acutting device that has a slider movable in a direction inclined withrespect to an axis of the coiling mandrel and a blade attached to theslider, and cuts a bent wire in cooperation with the coiling mandrel. 2.The spring manufacturing machine according to claim 1, wherein thecoiling mandrel protrudes orthogonally to the wall, the cutting deviceis attached to the wall in a posture inclined with respect to the wall,and an angle of inclination of the cutting device with respect to thewall is not more than 30 degrees.
 3. The spring manufacturing machineaccording to claim 1, wherein an adjustment mechanism that adjusts theposture of the cutting device is provided.
 4. The spring manufacturingmachine according to claim 1, wherein the blade has a parallel portionparallel to the axis of the coiling mandrel, and the wire is sandwichedbetween the parallel portion and the coiling mandrel to be cut.